Only two of 91 national adaptation plans mention the AMOC, study finds

Brazil and Ireland are the two countries whose plans mention the AMOC, according to the study. Brazil devotes a dedicated box to warning that a shutdown could push the Atlantic rain belt southwards and tip the Amazon rainforest towards collapse. Ireland, which relies on the AMOC to sustain its mild climate, says "reliance solely on adaptation may prove insufficient" and concludes that no national plan can prepare for such tipping points. The survey covers plans reported to the UN climate convention so far, so the two mentions amount to roughly 2% of the total. The study says the likelihood of a collapse is very difficult to quantify and its timing is highly uncertain.

What a slowdown would do

The AMOC carries warm water north from the tropics and helps regulate temperatures and rainfall far beyond the Atlantic. In northwestern Europe, losing that heat could bring winter cold extremes of -20°C in London. Climate model experiments in which the current is shut down show an average 29% weakening of the West African monsoon and a 19% weakening of the Indian summer monsoon, raising food and water risks in regions that depend on monsoon rain.

A full collapse, in which major ocean currents completely reorientate, is unlikely before 2100, the study says. A recent study cited by the researchers projected a 50% weakening of the AMOC by the end of the century under an intermediate emissions scenario. The AMOC has undergone dramatic changes before, including a near-complete shutdown around 17,500 years ago, after the coldest period of the last ice age.

Some governments are preparing

Some governments are not waiting for national plans to catch up. Iceland has declared an AMOC collapse a national security risk, the Netherlands is investigating what a slowdown means for its sea defences, and Finland is examining the consequences, POLITICO reported. The UK is spending millions on an early-warning system, and Nordic ministers have begun discussing the threat.

"It is irresponsible to wait for absolute certainty before preparing," Iceland's climate minister Jóhann Páll Jóhannsson told POLITICO. "This is not about panic or alarmism," he added. "It's just responsible governance."

The EU's green transition chief, Teresa Ribera, suggested last year adding the AMOC "to the list of national security acronyms in Europe."

Why the plans miss the risk

Most investments assume only gradual change, the researchers say. A reservoir built to cope with more variable rainfall may look like a bad investment if the rainy season instead becomes shorter and drier. The study outlines five ways policymakers can prepare, including identifying the investments and countries most at risk, stress-testing key projects against AMOC-collapse scenarios and favouring flexible solutions that can be adapted as conditions change.